Added information about creating a test/application module correctly.
Added information about creating a test/application module correctly.

PiperOrigin-RevId: 475917753
Change-Id: I832fa4c4c4340e10fce3da6325d5a9ed95870d07

androidx/androidx,androidx/androidx,AndroidX/androidx,androidx/androidx,androidx/androidx,androidx/androidx,AndroidX/androidx,AndroidX/androidx,AndroidX/androidx,AndroidX/androidx,androidx/androidx,AndroidX/androidx,androidx/androidx,AndroidX/androidx,androidx/androidx,AndroidX/androidx,AndroidX/androidx,androidx/androidx,androidx/androidx,AndroidX/androidx